| 摘要 |
PURPOSE:To obtain the switching circuit with a high reliability and a simple circuitry by providing a CR timer and a 3-terminal AC control ling element controlled thereby. CONSTITUTION:When an AC power supply terminal 1 is in a positive semicycle, a thyristor 8 is turned on by the current of a resistor 14, a constant voltage diode 23 and a thyristor gate 8c and the 3-terminal AC control ling element 4 is turned on with current flowing in via the anode 4c and gate 4a of the element 4 and a capacitor 6 due to the voltage drop of the resistor 7 so that power is supplied to an AC load 3b. When the terminal 1 is in a negative semicycle, the element 4 is similarly turned on by the discharge current of the capacitor 6 so that power is continuously supplied to the load 3b. After a given space of time, a thyristor 21 is turned on through the operation of a CR timer circuit 19 and next the thyristor 8 and the element 4 are turned off so that the load 3b is cut off. Thereby, the switching circuit with a higher reliability than mechanical contact such as a centrifugal switch can be obtained. |
